Jonathan Amos,a BBC News Online science staff in Leicester UK, writes:
An attempt is being made to use a harmless version of HIV to help prevent the rejection of transplanted hearts.
The virus, which causes Aids, is dangerous precisely because it has the great ability to integrate its own genetic material into that of ordinary non/dividing cells.
Researchers at Cambridge University, UK, are exploiting this feature to get genes into a donated organ that will tell the body's immune system not to attack it.
If they can make the approach work, it could substantially improve the survivability of transplant patients. The technique is also being tested by other groups on brain and liver cells / major targets for the treatment of disease and in particular genetic disease.
"I'd much rather HIV didn't exist but it has given us a unique property which is the capability of delivering genes into particular cells," Dr Andrew Lever told the BBC.
Some years ago, Dr Lever's team unravelled the signalling process that HIV uses to load new virus particles with genetic material. This knowledge is now being used to insert therapeutic genes / genes that will aid the body's recovery, not infect it.
"We've tagged the little signal that gets RNA into a virus particle on to useful genes and then we can use the virus as an envelope to deliver the genes to new cells."
Dr Lever is now exposing rats that have had heart transplants to HIV that will help stop their new organs being rejected as foreign material by their own immune systems.
"We inject genes into the heart tissue that will secrete a molecule that suppresses the immune system in the local vicinity. The idea is that the heart transplant area would act as an immunologically privileged site and would be protected against rejection / and hopefully the organ would last longer."
For the future scenario Dr Lever says current work by his and other groups in this area has been encouraging. Dr Lever stressed the viruses used were no more than shells, lacking any of their own harmful genetic material, making the therapy completely safe.
"We modify the virus hugely so that it's not capable of regenerating into a wild type virus," he said. "I really look forward to the day when we've conquered HIV in its wild form and are using its useful characteristics to treat diseases / using methods we haven't got at the moment."
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